Emmet Shelton Bridge Structural Analysis and Rehabilitation

CA performed a four phase investigation of an existing 1940’s composite steel and concrete bridge spanning the Colorado River in Austin, Texas. Phase I consisted of  full-scale instrumentation and load testing, including performing a preliminary structural analysis and providing  consulting engineering services related to the emergency transport of heavy loads across the bridge well in excess of the rated capacity of the structure. Phase II included a condition survey of the superstructure and substructure which involved photographic documentation of the existing structural conditions, testing of the existing concrete, underwater inspection of the bridge foundation, installation of strain gauge monitoring devices, and addressing safety issues regarding traffic. Phase III involved the continued monitoring of the in-service behavior of the bridge in addition to performing a life-cycle analysis of the structure in its present condition based on the field data obtained in Phase II. Phase IV consisted of the design of repairs for the superstructure and substructure and construction administration and inspection of the implementation of the rehabilitation.

Non-Destructive Testing Services at Dos Hermanos Bridge

The Dos Hermanos Bridge structure, built in 1981, is one of the two ground-level links between the Islands of San Juan and Puerto Rico. As a result of the severe marine environment exposure conditions, a few years after its completion, the bridge showed signs of early deterioration including severe corrosion of the concrete reinforcement in both the cast-in-place and the precast, prestressed structural members. CA performed a field condition survey and assessment of the structural integrity and safety of the structure including, among other things, destructive and non-destructive concrete testing, chloride ion content testing to determine the chloride ion penetration into the concrete, and cover meter scanning to determine the location of existing reinforcement. Furthermore, a service life cost estimate analysis and predicted service life expectancy was prepared based on various modeling techniques considering the in-service conditions, the implementation of different concrete restoration and rehabilitation techniques, and the actual properties, characteristics, and performance of the concrete.

Assessment of a Cast-In-Place Post-Tensioned Concrete Parking Garage

A four story, cast-in-place concrete parking garage consisting of an elevated pan-joist slab system framed by post-tensioned concrete beams provided a parking area and a structural frame foundation for a three story commercial office building. The elevated ramps for the parking garage exhibited distress in the form of full depth cracking in the elevated slabs parallel and adjacent to the post-tensioned beams and perpendicular to the longitudinal direction of the intermediate joists allowing for moisture migration and efflorescence to form on the underside of the elevated slab along the length of the cracks. CA performed, among other things, a detailed condition assessment of the structure, including crack maps of the entire parking structure, a review of drawings and plans, and a structural analysis of the post-tensioned beam and joist framing system accounting for their support and restraint conditions. CA determined the causes of the observed distress and developed recommendations for concrete crack repair and remediation of the reinforced concrete structure.

ABIA Passenger Terminal

CA was retained by the City of Austin to perform a condition assessment of the precast parking garage structure, evaluate the design of canopies in the rental car area, and provide recommendations for the repair and rehabilitation of the parking garage and canopies, pedestrian bridges, elevated roadway, and entrance/exit ramps in the Austin – Bergstrom International Airport (ABIA) located in Austin Texas. The parking garage at the ABIA is a three-level precast concrete structure which encompasses approximately 1.2 million square feet. Distress areas in the parking garage structure included cracking, spalling, and deterioration of the joints. The structural steel canopies cover all parking garage spaces on the third floor rental car level. Distress in the canopies was observed in areas of the expansion joints, attachment to the metal roof deck, supporting members, base plate connections, and concrete columns in the aforementioned. Repair recommendations included the replacement and repositioning of bearing pads, repair of cracking and spalling, installing lateral bracing of supporting members, tightening base plate columns, and repairing the concrete columns, among others. CA designed the retrofit for the structural members and worked directly with the contractor during the rehabilitation of the structure.

Other Selected Airport Experience

Other airport-related projects include, among others, work performed on the runway pavement at the Denver International Airport, Puerto Rico’s Luis Muñoz Marín Int’l Airport, taxiway at Houston’s Hobby Airport, and several military installations.